ABSTRACT
A haptic interface is a motorized and instrumented device that allows a human user to touch and manipulate objects within a virtual environment. As shown in Figure 23.1, the haptic interface intervenes between the user and virtual environment, making a mechanical contact with the user and an electrical connection with the virtual environment. At the mechanical contact, force and motion are either measured by sensors or driven by motors. At the electrical connection, signals are transmitted that represent the force and motion occurring at a simulated mechanical contact with a virtual object. A controller within the haptic interface processes the various signals and attempts to ensure that the force and motion signals describing the mechanical contact track or in some sense follow the force and motion signals at the simulated contact. The motors on the haptic interface device provide the authority by which the controller ensures tracking. A well-designed haptic device and controller will cause the behaviors at the mechanical and simulated contacts to be “close” to one another. In so doing it will extend the mechanical sensing and manipulation capabilities of a human user into the virtual environment.
